Yelloe Alysum

Last year at whenever the correct time was i sowed some yelloew allysum and i have planted a couple of the survivors on a south facing stone wall. They are just coming into flower but i have planted them too near some for get me nots that i also sowed last year. I'm delighted they are all coming through. Is it poss to move the allysum to a spacier place now when it is coming into flower. I would hate to lose something that i have succeeded in growing from seed but they do look very crowded and there are big gaps nearby waiting to be filled..